Michael Yarish/AMC

Big Fat Lie

Everything You Know About Fat Is Wrong

05.07.14 9:45 AM ET

You can’t blame patients for being skeptical. After years of advocating low-fat diets, Dr. Oz recently declared that eating saturated fat might not actually be all that bad. And the month before that, the press hyped a new study that indicated there’s no good evidence that saturated fats cause heart disease. The American Heart Association, on the other hand, continues to promote low-fat diets. So what should physicians tell patients now?

Most practicing doctors are poorly equipped to make sense of it all. (Even the doctors on the 2013 cholesterol guideline committee hired other peopleto read the literature for them.) What should doctors advise—stick with low fat or start cooking with lard?

In the new book, The Big Fat Surprise: Why Butter, Meat and Cheese Belong in a Healthy Diet, science writer Nina Teicholz implies that we should do the latter. Like many people, Teicholz herself was once a disciple of low-fat diets—but after she took an assignment writing restaurant reviews, she found herself losing weight on a diet of heavy creams and fatty meats. Her curiosity was piqued, and she began a nearly decade-long critical review of the research on dietary fat. Her conclusion? Eating saturated fat can be the key to developing a healthy and lean body.

However, in order not to over-consume calories, eating more fat implies eating less carbohydrates. Indeed, these low-carb-high-fat (LCHF) diets are back in vogue with the rise of the Paleo movement—partly because people are beginning to question if increased carb intake has caused soaring obesity rates. Besides, for weight loss, low-fat diets yield only modest results and for some people don’t work at all.

That was the case for Dr. Peter Attia, who was featured on Dr. Oz’s show. Attia is a former Johns Hopkins surgeon who followed a low-fat diet and worked out several hours a day, but he was still overweight. Eventually, he developed metabolic syndrome—a condition that presages diabetes and heart disease. But he was able to lose the excess pounds and reverse his metabolic syndrome by dropping simple carbs and, in the process, eating more fat.

Dr. Attia’s story belies the popular misconception that the obese are simply lazy and gluttonous or too dumb and undisciplined to stick to a diet. Just maybe, what’s really making people fat are their hormones—in this case insulin, which, in susceptible people, spikes too high after a carbohydrate meal and locks energy into fat tissue.

This hypothesis was the work of pre-World War II German and Austrian researchers and came of age in the U.S. in the 1950s. It was given mainstream respectability in 2002 by science writer Gary Taubes in the New York Timesarticle, “What If It’s All Been a Big Fat Lie?” Taubes went on to write two books on the topic. While for many people Taubes’ work has helped reframe the thinking about why we get fat, some influential academicians remain unconvinced.

But many practicing physicians are prescribing LCHF diets anyway—simply because they’re so effective. In fact, Dr. Rakesh Patel, a family practitioner in Arizona, has seen enormous improvements in very sick patients. “These patients are honestly trying to make a go of it with low fat,” Patel told The Daily Beast. “But they come back after their third, fourth, or fifth [cardiac] stent—and I put them on a [LCHF] diet and they get better. A cardiologist sent me a patient recently, and after three months she’s down 25 pounds, her cholesterol is normal, and her LDL-particles are down by 1,000 [with the change in diet alone]. Her energy is good, she feels great.”

Dr. Patel has been prescribing LCHF diets for the last four years and, like other doctors around the country, he’s had some astonishing results. He’s even been able to demonstrate reversal of atherosclerotic plaque. When asked why he’s comfortable prescribing a high-fat diet to cardiac patients when the AHA still promotes low-fat diets, Patel says he believes the science is actually on his side.

“For 80% of people with cardiovascular disease, it’s a glycemic [sugar] issue. That’s been shown over and over again in the literature. Even back in 1999 with the DECODE study in The Lancet,” he says. “It’s the carbohydrate that’s the elephant in the room.”

But for the over-worked, guideline-driven doc-in-a-box, low-carb diets still have a daunting public relations battle to overcome. Vocal opponents to LCHF diets insist the diet simply makes you sick, akin to using chemotherapy or amphetamines to shed pounds. Using the diet will, according to low-fat diet doctor Dean Ornish, “mortgage your health.”

Dr. Ornish became famous in the 1990s for showing reversal of coronary artery disease using a very low-fat, near-vegetarian diet. Since then, other doctors, like Caldwell Esselstyn, MD, have used no-added-fat vegan diets even more effectively to reverse atherosclerotic plaque. It may seem difficult for the two approaches to live comfortably together.

But Dr. Patel doesn’t see it that way. “Those diets are also low-carbohydrate diets—it doesn’t really matter if you fill the background with plants or with fat. There’s more than one way to skin a cat,” Patel says. “But I like low-carb/[high-fat] because in my experience, I’ve found it easier for patients to stay compliant.”

The two approaches have a couple of other things in common. Proponents both disagree with the American Heart Association dietary recommendations for 25-35% of daily calories as fat (7% as saturated fat)—too high for one camp, too low for the other. And proponents of both are equally dismissive of each other. “I find it ironic,” Dr. Patel says, “that people on each side are more than willing to support their beliefs with clinical anecdotes, but attack the other side for doing the same.”

This has been a theme in nutrition policy since the beginning. Both sides have an almost religious certainty they are right, and both feel they are fighting for patients’ health. “Nutrition science is a blood sport,” Nina Teicholz concluded after nearly a decade observing how science gets done. “When the science is weak, it's all about the politics. That’s been the theme of my book.” And many people agree: with nutrition science, it’s been hard to get to the truth.

“This is not the kind of thing you can dial in from doing a big study,” says Dr. Patel. “You have this heterogeneous population and one diet may not be ideal for another patient. This is where personalized medicine comes in—doctors have to get comfortable dealing with that.”

To be sure, the “truth” may be that a low-carb/high-fat diet is not the answer for every patient. But saturated fats appear to have been decriminalized. With Dr. Oz’s reversal—and the hard work of many patients and physicians—conventional doctors have something else to offer patients who are failing conventional treatment. If history is any guide, doctors and patients can’t afford to wait for the science to get better. It may never be good enough.